JPH0210754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air pressure booster used in a brake device or the like.

Generally, a pressure booster that uses the engine's intake pipe pressure to double the brake pedal depression force and transmit it to the master cylinder has two chambers inside the main body, a front chamber and a rear chamber. The power piston unit includes a first passageway having one end opening into the front chamber and the other end opening into the inside of the power piston unit, and a first passage having one end opening into the rear chamber and the other end opening inside the power piston unit. A second passage that opens is bored, and a valve mechanism is provided inside the power piston unit to control the opening and closing of the first passage and the second passage in conjunction with the input shaft, and the inside of the power piston unit is There is something that communicates with the atmosphere. And, such a pressure booster operates the input shaft to switch the valve mechanism, and creates a pressure difference between the front chamber and the rear chamber by switching the valve mechanism,
The thrust force acting on the power piston unit due to the pressure difference is transmitted to the output shaft.

By the way, in this type of conventional booster, when the valve mechanism closes the first passage and opens the second passage, atmospheric air flows into the rear chamber, and then the valve mechanism closes the first passage and opens the second passage. When the switch is switched to open the first passage and close the second passage, the atmosphere in the rear chamber flows out due to negative pressure in the intake pipe of the engine, and in each of these cases, the inside of the booster Operating noise is generated by the working fluid flowing through. Particularly, in a one-box type vehicle in which the entire booster is installed in the driver's cab, the operating noise of the working fluid flowing inside the booster is extremely loud, and there is a strong desire to reduce the operating noise.

The present invention was made in view of the above circumstances, and
The purpose is to reduce the operating noise of the working fluid flowing within the air pressure booster.

In order to achieve this object, the present invention has a structure in which a branch passage for branching the flow of the working fluid is formed on the front chamber side of the first passage of the power piston unit.

From the above-mentioned configuration, the working fluid flowing through the first passage has a flow rate reduced and the flow is rectified by passing through the branch passage.
The operating noise in the pressure booster using the working fluid is reduced.

Hereinafter, in order to further clarify the present invention, several embodiments thereof will be described with reference to the drawings.

In FIGS. 1 to 3 showing the first embodiment, 1
1 is a main body of the air pressure booster, and the main body 1 consists of a front shell 1A and a rear shell 1B.The inside of the main body 1 is divided into two chambers, a front chamber 3 and a rear chamber 4, by a power piston unit 2. ing.
Note that an engine intake pipe 25 opens into the front chamber 3. This power piston unit 2
The valve body 5 generally includes a valve body 5, a diaphragm 6, a piston plate 7, and a disk holder 8. The valve body 5 extends outside the main body 1 by penetrating the rear shell 1B, and extends in the left-right direction (hereinafter referred to as
This direction is referred to as the front-rear direction). Cylinder portion 5a of the valve body 5
A plunger 9 is inserted into the plunger 9, and the plunger 9
The spherical end of the rod 10 is fitted into the recess 9a, and the other end of the rod 10 is fitted with a spherical end.
It is connected to a brake pedal (not shown),
The plunger 9 and rod 10 constitute an input shaft. The plunger 9 and the cylinder portion 5a of the valve body 5 each have a valve seat 9 at their rear end.
b, 5b are formed, and a poppet valve 11 is provided in the valve body 5 behind the valve seats 9b, 5b.
The poppet valve 11 is urged by a spring 12 so as to be able to come into contact with and separate from the valve seats 9b and 5b. In addition, when it is not activated, the first
As shown in the figure, the poppet valve 11 has a valve seat 9.
b, 5b. This valve body 5 has one end opening into the front chamber 3 and the other end opening into the valve seat 5b.
the valve body 5 which is rearward than the poppet valve 11 and forward of the attachment part of the poppet valve 11 to the valve body 5;
A first passage 13 that opens inward and a valve body 5 that has one end that opens into the rear chamber 4 and the other end that is forward of the valve seat 5b.
A second passage 14 opening inward is bored.
The first passage 13 is bored in the valve body 5 so that its cross-sectional area in the direction of extension is constant. As mentioned above, since high precision is required to drill each passage 13 so that its cross section is constant, machining is preferably used. Incidentally, in the past, the cross-sectional area expanded toward the front chamber 3, and the operating noise generated by the atmosphere inside the valve body 5 was amplified due to the perforation shape (so-called tsupa shape), and the cross-sectional area expanded toward the front chamber 3. It was transmitted to However, with the above configuration, the operation noise generated in the valve body 5 due to the atmosphere is prevented from being amplified.
Therefore, when inactive, that is, when the poppet valve 11 and the valve seats 9b, 5b are in contact with each other,
Communication between the front chamber 3 and the rear chamber 4, both chambers 3 and 4, and the atmosphere as a working fluid source (the area behind the poppet valve 11 in the valve body 5 communicates with the atmosphere) is cut off, and the poppet valve 11 and the valve seat are disconnected from each other. 5b
When the poppet valve 11 and the valve seat 9b are separated from each other while in contact with each other, only the rear chamber 4 and the atmosphere are communicated with each other.

A disk holder 8 is fixed to the front surface of the valve body 5 via a diaphragm 6 and a piston plate 7. A through hole 15 is formed in the disk holder 8.
5 is a large diameter part and a small diameter part 15 whose diameter is reduced from the large diameter part.
It consists of b. The tip of the plunger 9 faces the small diameter portion 15b, and the output shaft 1 faces the large diameter portion 15a via the reaction disk 16.
The large-diameter proximal end portions 17a of No. 7 are engaged with each other, and the input shaft and output shaft 17 are arranged on the same axis. Further, in a portion of the rear surface of the disk holder 8 facing the opening of the first passage 13, a fan-shaped recess 8a serving as a buff-full member is provided at a substantially right angle to the direction in which the first passage 13 extends. It is formed to close the front surface of the valve body 5 and the disk holder 8.
A space 18 is formed by the rear surface of the . Furthermore, the disk holder 8 has the space 1
In the circumferential range approximately surrounding 8, Figures 2 and 3
As shown in the figure, a plurality of notches 8b are formed radially outward from the concave portion of the disk holder 8, and the disk holder 8 and the piston plate 7 communicate the space 18 and the front chamber 3. A plurality of communicating holes 19 are formed. The length of each communication hole 19 becomes shorter from the bottom to the top in FIG. 3 depending on the shape of the disk holder 8. The space 18 formed by the recess 8a and the communication hole 19 constitute a branch channel of the present invention.

A support plate 20 is installed on the inner wall of the rear shell 1B.
A rod 31, which is held between the support plate 20 and the rear shell 1B, passes through the power piston unit 2 and the front shell 1A, and its tip extends outward from the main body 1.
A nut 22 is screwed into a threaded portion 21 formed at the tip of the rod 31. This rod 31 is surrounded by a bellows 23 in the front chamber 3. The front end of the bellows 23 is fixed to the inner wall of the front shell 1A, and the rear end is fixed to the power piston unit 2. In addition, the front shell 1A in the front chamber 3
A return spring 24 is provided between the power piston unit 2 and the power piston unit 2 for biasing the power piston unit 2 rearward.

Note that 26 is a porous member having a function of dividing the air, and the porous member 26 also reduces the operational sound energy of the air flowing inside the porous member 26.

Next, the effect will be explained.

Rod 10 by depressing the brake pedal.
When forward thrust is applied to the piston unit 2, the plunger 9 moves forward inside the stationary power piston unit 2, the valve seat 9b of the plunger 9 separates from the surface of the poppet valve 11, and at the same time, the atmosphere fills the gap and the valve. It enters the rear chamber 4 through the second passage 14. At this time, the poppet valve 11 is in contact with the valve seat 5b of the valve body 5 even before the brake pedal is depressed. Due to the introduction of this atmospheric pressure, the diaphragm 6
A differential pressure is generated on both sides of the piston, a forward thrust is generated in the power piston unit 2, and a boosting operation is started. The thrust of this power piston unit 2 is transmitted to the output shaft 17, and the thrust of the power piston unit 2 is transmitted to the output shaft 17.
7 is pressed forward. At this time, the output shaft 17
The reaction force in the rearward direction is transmitted to the power piston unit 2, while the reaction force from the
6 is elastically deformed and comes into contact with the plunger 9, and as a result, the force is transmitted to the brake pedal via the plunger 9 and the rod 10. diaphragm 6
Due to the forward movement of the power piston unit 2 accompanying the forward movement of the valve, the valve seat 9b of the plunger 9 seats on the poppet valve 11 and becomes stationary, but if the brake pedal is further depressed, the same operation will be performed. becomes.

When the brake pedal is released, the rearward reaction force from the output shaft 17 is transmitted from the plunger 9 to the poppet valve 11, and the poppet valve 11 is separated from the valve seat 5b of the valve body 5 and released from the atmosphere in the rear chamber 4. flows out into the front chamber 3 via the first passage 13. Therefore, as the pressure in the rear chamber 4 decreases, the differential pressure between the front chamber 3 and the rear chamber 4 decreases, and the return spring 24 causes the power piston unit 2 to return to the original position shown in FIG. At this time, from the rear chamber 4 to the first passage 1
The air flowing out through the disk holder 8 hits the recess 8a of the disk holder 8 and is subjected to a so-called buffling effect, and its kinetic energy is wasted. Then, the atmospheric air is temporarily accumulated in the space 18 formed by the disk holder 8 and the valve body 5 to suppress pulsation, and then the atmospheric air is released in a branched state through the plurality of communication holes 19 to the front chamber 3. Ru. Each of these communication holes 19 contributes to reducing the flow velocity and rectifying the flow of the atmosphere, so that when the brake pedal is released, the air flowing from the rear chamber 4 to the front chamber 3 is Recess 8a, space 1
8. Each communication hole 19 reduces the flow velocity and rectifies the flow in several stages, reducing the energy of the operating noise caused by the atmosphere and lowering the operating noise.

Next, another embodiment will be described. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals, and the explanation thereof will be omitted.

4 and 5 show a second embodiment, in which a holder 27 having a function of preventing the large diameter base end 17a of the output shaft 17 from coming off and the front surface of the power piston unit 2 is used to divide the flow of the present invention. A plurality of communication holes 19, which are channels, are formed in the circumferential direction of the holder 27. In this embodiment, the holder 27
Since only simple processing is required, manufacturing is easy.

FIG. 6 shows a third embodiment, in which a first passage 13 is provided in the disk holder 8 and the piston plate 7.
A through-hole 28 is formed, and a porous member, for example, a filter 29 made of sponge, is attached to the through-hole 28 and the second passage 14. As a result, the flow velocity of the air flowing into the filter 29 is reduced by the filter 29, and the flow is rectified, so that the operating noise due to the air is reduced.
That is, this filter 29 can also be considered to form a branch channel from a microscopic point of view. Of course, filter 29
may be attached only to either the through hole 28 or the second passage 14. Therefore, when the filter 29 is installed in the second passage 14, of course, and when the filter 29 is installed in the through hole 28 and the second passage 14, both when the brake pedal is depressed and when it is released. In both cases, operating noise due to the atmosphere can be reduced. Particularly in the latter case, it goes without saying that it is effective in reducing operating noise.

In the above embodiments, the case where the front chamber 3 and the rear chamber 4 are in a vacuum-atmosphere relationship during boosting operation has been described, but the present invention is not limited to this.
may have a relationship such as vacuum-compressed air or atmosphere-compressed air.

As described above, in the present invention, a branch channel is formed on the front chamber side of the first passage to branch the flow of the working fluid, so that the working fluid is operated by reducing the flow velocity and rectifying the flow. Since the operating sound energy due to the fluid is reduced, the operating noise of the working fluid is reduced.
It can be made as small as possible. In addition, the branch channel is
Since it is formed in the front chamber side of the first passage where the valve mechanism is not provided, the valve mechanism etc. do not get in the way and can be easily formed.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing a first embodiment of the air pressure booster according to the present invention, and FIG.
A line sectional view, FIG. 3 is a view showing the main part of the rear surface of the disk holder, FIG. 4 is a longitudinal sectional view showing a second embodiment of the air pressure booster according to the present invention, and FIG. A view seen from direction B in FIG. 4 and FIG. 6 are sectional views of main parts showing a third embodiment of the air pressure booster according to the present invention. 1...Main body, 2...Power piston unit,
3...Front chamber, 4...Rear chamber, 5...Valve body, 5b...Valve seat, 9...Plunger, 9b
... Valve seat, 10 ... Rod, 11 ... Poppet valve, 13 ... First passage, 14 ... Second passage, 1
7... Output shaft, 19... Communication hole, 29... Filter.

Claims (1)

[Scope of Claims] 1. The inside of the main body is divided into two chambers, a front chamber and a rear chamber, by a power piston unit, and the power piston unit has one end opening into the front chamber and the other end opening inside the power piston unit. A first passageway opening into the rear chamber and a second passageway opening into the rear chamber at one end and opening into the inside of the power piston unit at the other end, the inside of the power piston unit interlocking with the input shaft. a first passage and said second passage;
A valve mechanism for controlling opening and closing of the passage is provided, the inside of the power piston unit is communicated with a working fluid source having a relatively higher pressure than the front chamber, and the input shaft is actuated to switch the valve mechanism to open and close the two chambers. In the air pressure booster, the thrust force acting on the power piston unit is transmitted to the output shaft when a pressure difference is generated between the power piston units, and the flow of the working fluid is directed to the front chamber side of the first passage. A pressure booster characterized by forming a diversion channel for dividing the flow. 2. In claim 1, the first passage extends in the axial direction of the power piston unit, and is closed on the front chamber side, and the branch passage extends in the axial direction of the power piston unit. An air pressure booster comprising a plurality of communication holes formed in a direction intersecting the extending direction of the passage and communicating with the front chamber.